The present invention relates to apparatus for the successive release of separated items of mail from a stack. Apparatus of this type generally includes a removal member which is continuously in engagement with the foremost item while circulating under controlled conditions so as to advance successive items into the effective range of a pair of permanently driven conveying rollers, a first sensing device disposed between the stack outlet and the conveying rollers, a second sensing device spaced from the first device, and a control circuit which controls the drive of the removal member in dependence on the signals from the sensor devices so that the next item follows the trailing or leading edge, constituting a reference edge, of the previously separated item with a spacing which corresponds to the spacing between the sensing devices.
Separating devices of this type are disclosed, for example, in German Offenlegungsschrift [Laid-Open Application] No. 24 10 145. In that apparatus, a sensing member, such as in particular a single light barrier, is disposed between the stack output and the conveying rollers and the position of this sensing member defines a uniform waiting position for all items.
The control circuit is designed so that the drive of the removal member is switched on only if either the sensing member is enabled or the sensing member is blocked and a call signal is present at the control circuit, and the braking time upon stoppage of the removal member and the distance between the sensing member and the conveying rollers are selected so that the removal member pushes each item up to the sensing member and, only after receiving a call signal, pushes it on to the effective range of the conveying rollers. The call signal which is given to the control circuit is the output signal from a second sensing member which follows after the conveying rollers and which is actuated by the passage of the respective reference edge of the previously discharged item.
Accordingly, in the known devices each item to be separated is accelerated twice by the removal member: once during the advancement to the waiting position at the first sensing member and a second time during the advancement from the waiting position into the effective range of the continuously driven conveying rollers. This requires a correspondingly frequent actuation of the drive for the removal member or for the brake coupling, respectively, which is utilized to control it.